Smalltalk

The intended “searchQuick” (sQuick) is an application to enable a user to search a set of books or texts, like an encyclopedia, or some other topical book collection offline built in the open source platform Pharo 4.0.

Bringing up to the rear of the summers, the project was brought to a penultimate stage by achieving the following tasks:

This post aims to put forward the basics of Build Automation and also brief the steps required to put up a Pharo application on Continuous Integration, Inria which is a platform for Scheduled Automated Build.

For simplicity, Build automation is the act of scripting or automating a wide variety of tasks that software developers do in their day-to-day activities including things like:

compiling computer source code into binary code

packaging binary code

running automated tests

deploying to production systems

creating documentation and/or release notes

Various types of automation are as:

On-Demand automation such as a user running a script at the command line

Scheduled automation such as a continuous integration server running a nightly build

Triggered automation such as a continuous integration server running a build on every commit to a version control system.

In recent years, build management tools have provided relief when it comes to automating the build process.

The dominant benefits of continuous integration include:

Improvement of product quality

Acceleration of compile and link processing

Elimination of redundant tasks

Minimization of ‘bad builds’

Have history of builds and releases in order to investigate issues

Save time and money – because of above listed reasons.

A build system should fulfill certain requirements.

Basic requirements:

Frequent or overnight builds to catch problems early.

Support for Source Code Dependency Management

Incremental build processing

Reporting that traces source to binary matching

Build acceleration

Extraction and reporting on build compile and link usage

Optional requirements:

Generate release notes and other documentation such as help pages

Build status reporting

Test pass or fail reporting

Summary of the features added/modified/deleted with each new build

Considering the above mentioned advantages of automated build, the below enlisted steps will help to put up your own Pharo application hosted on github on the CI server for continuous integration/scheduled build.

14. The main task is to carefully write the commands in the ‘Execute Shell‘
The default commands are as:

15. After saving and applying the changes, the application is all set for automated build.

16. Each build’s ‘Console Output‘ can be used to analyse the steps and highlight the weak areas of the project.
For instance: The below output is of a project whose stable version build was successful.

TIP: Keep a regular tab on the build results and analyze each line of the Console Output with utmost care.

Hope this post was able to help you start with the automation build process of Pharo Application.

Do like if it was worth a read !Post queries/suggestions as comments 🙂 Looking forward to them.

UPCOMING: Next, I plan to share experience of putting up my Pharo application searchQuick on CI Inria for automated build. I intend to detail about the various configuration settings applied along with the Execute Shell commands utilized for a GitHub project 🙂

The intended “searchQuick” (sQuick) is an application to enable a user to search a set of books or texts, like an encyclopedia, or some other topical book collection offline built in the open source platform Pharo 4.0.

After the chief tasks of search functionality and automated build were done with, the next undertaking included working on finer details and embellishments.

The intended “searchQuick” (sQuick) is an application to enable a user to search a set of books or texts, like an encyclopedia, or some other topical book collection offline built in the open source platform Pharo 4.0.

The main task achieved was putting up the application up on Continuous Integration, Inria for automated build. It was indeed a beneficial idea as it helped me keep a check on the builds and work on issues.
Being a newbie, this work was cumbersome initially but with the help of my mentors and the #pharo community, I was able to accomplish it. To assist fellow Pharo-ers, I have compiled all the information regarding CI Automated Build for yout Pharo Application and published the same on my blog-spot. Kindly go through it for a complete understanding 🙂

The intended “searchQuick” (sQuick) is an application to enable a user to search a set of books or texts, like an encyclopedia, or some other topical book collection offline built in the open source platform Pharo 4.0.

As the rudimentary structure of the application is sewn up, embellishment of GUI and rigorous testing are the major part of course of action.

On eMBee’s ( +Martin Bähr ) suggestion to build up an accordion widget to display the search results, various trials were conducted to design a similar one in Pharo.

The task of developing the accordion widget in Pharo was achieved using Expander Morphs. Looping through the search results array, a #newExpander: was added in each #newRow: of the modal built.

A challenging chore was to add a scroll-able content on the click of the desired search result expander. Sundry experiments with #newLabel: and #newText: in #newScrollPaneFor: {i.e. adding text model and labels in scroll pane} had no effect. Eventually, #newTextEditorFor: did the trick and the desired look was created.

Next on the cards is putting up sQuick for automated build on the CI Server, as suggested by +Sean DeNigris for its various advantages which include:

Improvement of product quality

Acceleration of compile and link processing

Elimination of redundant tasks

Minimization of ‘bad builds’

Have history of builds and releases in order to investigate issues

Save time and money – because of above listed reasons.

For simplicity, Build automation is the act of scripting or automating a wide variety of tasks that software developers do in their day-to-day activities including things like:

compiling computer source code into binary code

packaging binary code

running automated tests

deploying to production systems

creating documentation and/or release notes

UPCOMING:

To achieve Build Automation for sQuick, I have already registered on CI and configured sQuick.
Next endeavor is to look into the red signal in the build evaluation.

So, while I was browsing through various developments in Pharo, I came across a very eye-catching paper on Bootstrapping Reflective Systems: The case of Pharo .

For beginners, Bootstrapping is basically the process of writing a compiler or an assembler in the source programming language in which it is intended to compile. Applying this technique leads to self-hosting compiler that proceeds without external input.

Though, I am still a newbie and in the process of grasping all this ingenious stuff.
But I am sure that this paper ( Poli12-BootstrappingSmalltalk-SCP ) by G. Polito , S. Ducasse , L. Fabresse , N. Bouraqadi , B. van Ryseghem would make for an interesting read.

This post aims to provide a basic overview of what PharoLauncher is and give a step-by-step approach on how to use this application of great advantage.

Overview

Pharo is an open source implementation of the programming language and environment Smalltalk. Pharo is not Smalltalk. Pharo is Smalltalk-inspired.

Pharo offers strong live programming features such as immediate object manipulation, live update, and hot recompilation. Live programming environment is in the heart of the system. Pharo also supports advanced web development with frameworks such as Seaside and more recently Tide.

The official Pharo website defines it as: ”Pharo is a pure object-oriented programming language and a powerful environment, focused on simplicity and immediate feedback (think IDE and OS rolled into one). ”

Pharo relies on a virtual machine that is written almost entirely in Smalltalk itself. Pharo environment is its own little world, designed around a conception of a computer with a minimal operating system and populated with living objects. A Smalltalk implementation is composed of an image (binary code), a major source file and a ‘changes’ file. The image is called Virtual Image (VI) because is independent of the platform you use for running Smalltalk. Smalltalk systems store the entire program state (including both Class and non-Class objects) in an image file. The image can then be loaded by the Smalltalk virtual machine to restore a Smalltalk-like system to a prior state.

As Pharo is open source, it growing rapidly owing to the contributions of people all around the world. Each day we have a new update of the image of Pharo which makes it cumbersome to keep track of updates. It becomes quite a task when one has to download a new image seperately each he/she plans to work on something having the latest issues fixed, new features added etc. That’s where the PharoLauncher comes in the picture. Pharo Launcher, a cross-platform application that

lets you manage your Pharo images (launch, rename, copy and delete);

lets you download image templates (i.e., zip archives) from many different sources (Jenkins, files.pharo.org, and your local cache) and create new images from any template.

The idea behind the Pharo Launcher is that you should be able to access it very rapidly from your OS application launcher. As a result launching any image is never more than 3 clicks away. “PharoLauncher” is useful to a user who develops and needs to constantly switch between images. PharoLauncher is also a very handy tool to download specific image update versions if you want to reproduce or fix Pharo bugs.Pharo Launcher is a Pharo-based application allowing you to manage a list of images (download, rename, delete) and switch between them without aditional tools.

Downloading/Installing PharoLauncher

As discussed earlier about the rapid evolvement of Pharo , kindly check out http://www.pharo.org/download to get the latest download/install instructions for Pharo Launcher.

If you don’t have the add-apt-repository command, install the software-properties-common package and try again. If you are on a server (no GUI), you can get a Pharo Virtual Machine by installing pharo-vm-core.

On Ubuntu, the Launcher is installed as /usr/bin/pharo, so you can type the following command on the terminal to start the Pharo Launcher.

MacOS:

Using PharoLauncher

Launch the Pharo launcher image using the platform-specific VM. The image below depicts how a PharoLauncher looks like when it is opened.

The screen displayed initially has been divided into two parts.

The left part ‘Existing Images’ displays the images already created by the user. Initially after the installation the left side with local images is empty. Whereas the the right side is the ‘Templates’ section which displays the image templates from various resources available for download from the internet. The ‘Existing Images’ section has 3 buttons : Launch, Delete and Refresh. The ‘Templates’ section has 2 buttons : Create Image and Refresh.

At the bottom of the launcher we have the buttons for quit and settings.

Select the image you wish to work on from the list and the sources provided in the ‘Templates’ section and download it. For instance you can download “Pharo4.0 (beta)” from the options provided which is the latest image as of today. By clicking on the ‘Create Image’ button at the top right corner.

Note that also the images from contribution CI are available. So you can easily download “Artefact”, “Moose”, … images according to your choice.

It will download the image into a specific directory somewhere in your users home directory. Each image gets an own folder. Use the “Show in folder” menu item to open this location.

The location of the images can be changed through the ‘Settings Browser’ option located at the bottom-right corner. Go to the ‘Open Settings’ > ‘Location of your images’. Now enter the desired path in the place provided as shown in the figure.

After ‘Creating an image’ , a dialog box appears which asks you to give a name to the image as shown in figure below.

After entering the suitable name , the image is displayed in the ‘Existing Images’ section.

To launch the image, simply select your option and click on the ‘Launch’ button located at the top right corner of the ‘Existing Images’ section and voila ! You have the pharo image of your choice running with the name of your choice.

The intended “searchQuick” (sQuick) is an application to enable a user to search a set of books or texts, like an encyclopedia, or some other topical book collection offline built in the open source platform Pharo 4.0.

After indexing the content and the next task that was covered was searching for the user input string. The #queryString: does a fantastic job as of now.
The search results were printed in a scroll-able pane by iterating through a loop so as to cover each and every existence of the desired string. The search results window also enables the user to view the content of the chosen file.

Search Results Display

Acting on the suggestion of my mentor, I have also loaded the Pharo image with text versions of large books (Thank You Project Gutenberg 🙂 ) to test the working of the search function.

UPCOMING

GUI Modification

Integrated Exhaustive Testing

Addition of help/tutorial

PS: The GUI of the application is under constant evolvement, Kindly ignore the poorly structured window 😛

The intended “searchQuick” (sQuick) is an application to enable a user to search a set of books or texts, like an encyclopedia, or some other topical book collection offline built in the open source platform Pharo 4.0.

After the GUI was designed with minimal features, the next task was to develop the cardinal search function.

That being, the index for sQuick was built using the Dictionary data structure in Pharo which works like HashTable of other programming languages/platforms.

index := Dictionary new.

Pharo describes a Dictionary as: “I represent a set of elements that can be viewed from one of the two perspectives: a set of associations, or a container of values that are extremely named where the name can be any object that responds to =. The external name is referred to as the key. I inherit many operations from the Set. “

The contents of the text files present in the current Pharo image were split at whitespaces and added to the index along with the corresponding file title.

tokens := ‘ ‘ split: aDocument contents.

The method #indexFiles was used to iterate over all the text files in the current Pharo image to index all the files before the searching begins.

Dictionary Entries after File Content Indexing

The #queryString method has been temporarily build using #includesSubstring which matches the user input string with all the entries of the index and gives the result in an array form with #tally output as the number of search results.

Various test methods are now built to inspect the functioning of the methods designed. Continuous debugging is being done to check out and remove errors, if any 😉

Tic-tac-toe (or Noughts and crosses, Xs and Os) is a paper-and-pencil game for two players, X and O, who take turns marking the spaces in a 3×3 grid. The player who succeeds in placing three respective marks in a horizontal, vertical, or diagonal row wins the game.

Because of the simplicity of Tic-tac-toe, it is often used as a pedagogical tool for teaching the concepts of good sportsmanship and the branch of artificial intelligence that deals with the searching of game trees. It is straightforward to write a computer program to play Tic-tac-toe perfectly, to enumerate the 765 essentially different positions (the state space complexity), or the 26,830 possible games up to rotations and reflections (the game tree complexity) on this space.

So , here we make a Pharo version of this well-known game by using Morph. This post provides a step-by-step approach on how to go about building this simple application.

A game package will be built having 3 subclasses :

TicTacToe

TicTacToeCell

TicTacToeModel

Initially , we have created TicTacToe a subclass of the Object class. The subclasses we will make will be combined in the package game as mentioned in the category: parameter.

A category name is not required in order for the class to work, but you will not be able to access the class to make changes or to look at existing code unless you provide a category name. (The category name used can be a new category name or the name of an existing category.)

The poolDictionaries: parameter is seldom used and will not be discussed here, and the category: parameter specifies the category under which this class will be grouped in the system browser.

As we know, a class encapsulates data values and methods, and every object contains a set of the data values and can receive any of the methods as a message. The data values in each object are specified by providing a set of names of variables whose values will be an object’s internal data values. Each object has its own set of these values, and the set of data values for an object represents the object’s state (or value). The variables that contain the data values of an object are called the instance variables for the object, and the instanceVariableNames: parameter is a list of names, separated by blanks, for the instance variables. In the above code snippet , we have declared container and model as two instanceVariables.

The classVariableNames: parameter lists the identifiers that are the names of variables shared by the class and all of its objects. That is, there is only one set of these, and they are used by the class and all of its objects. Class variables (so called because they belong to the class, of which there is only one, rather than to the objects that are instances of the class) are rarely needed.

An example of a class variable that could be useful is in a case where we wanted a unique “serial number” to be assigned to each instance of the class as it is created. The variable containing the next available (or last used) serial number would appropriately be a class variable, and each time a new instance (object) is created the serial number would be recorded as an instance variable value in the object and the serial number in the class variable would be incremented. Thus, each object can be serially numbered as it is created (without using one of those nasty global variables!).

After executing the code above, class TicTacToe will exist. However, it will have no methods other than those that are inherited from class Object. To make it useful, we must add the methods that are needed for our implementation.

The notation TicTacToe>>#initialize means that we have a method named initialize in the subclass TicTacToe.

In the initialize: method above , we have a container which is the instance of the class Morph (Morphic is the name given to Pharo’s graphical interface. ). We define the various attributes of the container such as layoutPolicy: and color:. model is another instance of the class TicTacToeModel which we will be creating further in this example.

self refers to the receiver of the message. It is usually used within a method to send additional messages to the receiver. self is frequently used when it is desired to pass the sender object (self), as a message argument, to a receiver who requires knowledege of the sender or who will in some way manipulate the sender.

The method addRows (the name is self explanatory) is used to add rows in the Tic Tac Toe grid. It declares temporary (local) variables rowMorph , aCell and rowCol which can’t be used beyond this method.

1 to:3 do:[ :row |

rowMorph := Morph new layoutPolicy: RowLayout new.

1 to: 3 do: [ :col |

aCell := TicTacToeCell new.

aCell setModel: (model) row: row col: col.

rowMorph addMorph: aCell.

].

The above code snippet works as a nested loop that runs thrice for each three rows to create a 3X3 grid as per requirement.

This method adds controls to the game. The local variables are : rowMorph , newGameButton and exitGameButton.

rowMorph defines an instance of the class Morph which would be the placeholder for the two control buttons located at the top. The two control buttons are defined as New using the variable new GameButton which on click would restart the game , and Exit using the exitGameButton which on click would close the game. The buttons are created using a method createCtrlLabelled which we define next.

rowMorph addMorph: newGameButton adds the button to the Morph instance created earlier.

It closes the game and calls for Garbage Collection (Garbage Collection (GC) is a form of automatic memory management. It finds data objects in a program that cannot be accessed in the future and reclaims the resources used by those objects.)

This initialize method initialises the button size as 80X80 and gives it the color: yellow. An ‘onClick’ control is given to the button which then calls the onClickExecutionBlock method present in the same class.

This method defines what should happen when each cell in the grid is clicked. At every click , the label of the cell is changed to X or O depending upon whose turn it is , the row numbers and coloumn numbers are updated in the parentModel and win condition is checked by calling the checkWinCondition method of the class TicTacToeModel defined next.